import {
  extractParamsFromPattern,
  formatRouteEntry,
} from "./param-extraction.js";
import { isAutoGeneratedRouteName } from "../../route-name.js";

// ---------------------------------------------------------------------------
// Code generation
// ---------------------------------------------------------------------------

/**
 * Generate a per-module types file from extracted routes.
 * Output has zero imports, preventing circular references.
 */
export function generatePerModuleTypesSource(
  routes: Array<{
    name: string;
    pattern: string;
    params?: Record<string, string>;
    search?: Record<string, string>;
  }>,
): string {
  const valid = routes.filter(({ name }) => {
    if (!name || /["'\\`\n\r]/.test(name)) {
      console.warn(
        `[rango] Skipping route with invalid name: ${JSON.stringify(name)}`,
      );
      return false;
    }
    return true;
  });

  // Deduplicate by name (first definition wins -- primary route before variants)
  const deduped = new Map<
    string,
    {
      pattern: string;
      params?: Record<string, string>;
      search?: Record<string, string>;
    }
  >();
  for (const { name, pattern, params, search } of valid) {
    if (deduped.has(name)) {
      console.warn(
        `[rango] Duplicate route name "${name}" — keeping first definition`,
      );
      continue;
    }
    deduped.set(name, { pattern, params, search });
  }
  const sorted = [...deduped.entries()].sort(([a], [b]) => a.localeCompare(b));
  const body = sorted
    .map(([name, { pattern, params, search }]) => {
      const key = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/.test(name) ? name : `"${name}"`;
      return formatRouteEntry(key, pattern, params, search);
    })
    .join("\n");
  return `// Auto-generated by @rangojs/router - do not edit\nexport const routes = {\n${body}\n} as const;\nexport type routes = typeof routes;\n`;
}

/**
 * Generates a .ts file that augments Rango.GeneratedRouteMap
 * with route name -> pattern mappings. This enables Handler<"routeName">
 * without circular references since the file has no imports from the app.
 */
export function generateRouteTypesSource(
  routeManifest: Record<string, string>,
  searchSchemas?: Record<string, Record<string, string>>,
): string {
  const entries = Object.entries(routeManifest)
    .filter(([name]) => !isAutoGeneratedRouteName(name))
    .sort(([a], [b]) => a.localeCompare(b));

  const filteredSearchSchemas = searchSchemas
    ? Object.fromEntries(
        Object.entries(searchSchemas).filter(
          ([name]) => !isAutoGeneratedRouteName(name),
        ),
      )
    : undefined;

  const objectBody = entries
    .map(([name, pattern]) => {
      const key = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/.test(name) ? name : `"${name}"`;
      const params = extractParamsFromPattern(pattern);
      const search = filteredSearchSchemas?.[name];
      return formatRouteEntry(key, pattern, params, search);
    })
    .join("\n");

  return `// Auto-generated by @rangojs/router - do not edit
export const NamedRoutes = {
${objectBody}
} as const;

declare global {
  namespace Rango {
    interface GeneratedRouteMap extends Readonly<typeof NamedRoutes> {}
  }
}
`;
}